(function(factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(['jquery'], factory);
    } else {
        // Browser globals
        factory(jQuery);
    }
} (function($) {
    $.timeago = function(timestamp) {
        // console.log(timestamp);
        if (timestamp instanceof Date) {
            return inWords(timestamp);
        } else if (typeof timestamp === "string") {
            return inWords($.timeago.parse(timestamp));
        } else if (typeof timestamp === "number") {
            return inWords(new Date(timestamp));
        } else {
            return inWords($.timeago.datetime(timestamp));
        }
    };
    var $t = $.timeago;
    $.extend($.timeago, {
        settings: {
            refreshMillis: 60000,
            allowFuture: false,
            localeTitle: false,
            cutoff: 0,
            strings: {
                prefixAgo: null,
                prefixFromNow: null,
                suffixAgo: "前",
                suffixFromNow: "from now",
                seconds: "1分钟",
                minute: "1分钟",
                minutes: "%d分钟",
                hour: "1小时",
                hours: "%d小时",
                day: "1天",
                days: "%d天",
                month: "1月",
                months: "%d月",
                year: "1年",
                years: "%d年",
                wordSeparator: "",
                numbers: []
            }
        },
        inWords: function(distanceMillis) {
            var $l = this.settings.strings;
            var prefix = $l.prefixAgo;
            var suffix = $l.suffixAgo;
            if (this.settings.allowFuture) {
                if (distanceMillis < 0) {
                    prefix = $l.prefixFromNow;
                    suffix = $l.suffixFromNow;
                }
            }
            var seconds = Math.abs(distanceMillis) / 1000;
            var minutes = seconds / 60;
            var hours = minutes / 60;
            var days = hours / 24;
            var years = days / 365;
            function substitute(stringOrFunction, number) {
                var string = $.isFunction(stringOrFunction) ? stringOrFunction(number, distanceMillis) : stringOrFunction;
                var value = ($l.numbers && $l.numbers[number]) || number;
                return string.replace(/%d/i, value);
            }
            var words = seconds < 45 && substitute($l.seconds, Math.round(seconds)) || seconds < 90 && substitute($l.minute, 1) || minutes < 45 && substitute($l.minutes, Math.round(minutes)) || minutes < 90 && substitute($l.hour, 1) || hours < 24 && substitute($l.hours, Math.round(hours)) || hours < 42 && substitute($l.day, 1) || days < 30 && substitute($l.days, Math.round(days)) || days < 45 && substitute($l.month, 1) || days < 365 && substitute($l.months, Math.round(days / 30)) || years < 1.5 && substitute($l.year, 1) || substitute($l.years, Math.round(years));
            var separator = $l.wordSeparator || "";
            if ($l.wordSeparator === undefined) {
                separator = " ";
            }
            return $.trim([prefix, words, suffix].join(separator));
        },
        parse: function(iso8601) {
            var s = $.trim(iso8601);
            s = s.replace(/\.\d+/, ""); // remove milliseconds
            s = s.replace(/-/, "/").replace(/-/, "/");
            s = s.replace(/T/, " ").replace(/Z/, " UTC");
            s = s.replace(/([\+\-]\d\d)\:?(\d\d)/, " $1$2"); // -04:00 -> -0400
            return new Date(s);
        },
        datetime: function(elem) {
            var iso8601 = $t.isTime(elem) ? $(elem).attr("datetime") : $(elem).attr("title");
            return $t.parse(iso8601);
        },
        isTime: function(elem) {
            // jQuery's `is()` doesn't play well with HTML5 in IE
            return $(elem).get(0).tagName.toLowerCase() === "time"; // $(elem).is("time");
        }
    });
    // functions that can be called via $(el).timeago('action')
    // init is default when no action is given
    // functions are called with context of a single element
    var functions = {
        init: function() {
            var refresh_el = $.proxy(refresh, this);
            refresh_el();
            var $s = $t.settings;
            if ($s.refreshMillis > 0) {
                setInterval(refresh_el, $s.refreshMillis);
            }
        },
        update: function(time) {
            $(this).data('timeago', {
                datetime: $t.parse(time)
            });
            refresh.apply(this);
        },
        updateFromDOM: function() {
            $(this).data('timeago', {
                datetime: $t.parse($t.isTime(this) ? $(this).attr("datetime") : $(this).attr("title"))
            });
            refresh.apply(this);
        }
    };
    $.fn.timeago = function(action, options) {
        var fn = action ? functions[action] : functions.init;
        if (!fn) {
            throw new Error("Unknown function name '" + action + "' for timeago");
        }
        // each over objects here and call the requested function
        this.each(function() {
            fn.call(this, options);
        });
        return this;
    };
    function refresh() {
        var data = prepareData(this);
        var $s = $t.settings;
        if (!isNaN(data.datetime)) {
            if ($s.cutoff == 0 || distance(data.datetime) < $s.cutoff) {
                $(this).text(inWords(data.datetime));
            }
        }
        return this;
    }
    function prepareData(element) {
        element = $(element);
        if (!element.data("timeago")) {
            element.data("timeago", {
                datetime: $t.datetime(element)
            });
            var text = $.trim(element.text());
            if ($t.settings.localeTitle) {
                element.attr("title", element.data('timeago').datetime.toLocaleString());
            } else if (text.length > 0 && !($t.isTime(element) && element.attr("title"))) {
                element.attr("title", text);
            }
        }
        return element.data("timeago");
    }
    function inWords(date) {
        return $t.inWords(distance(date));
    }
    function distance(date) {
        return (new Date().getTime() - date.getTime());
    }
    // fix for IE6 suckage
    document.createElement("abbr");
    document.createElement("time");
}));
